Alcohol burning stoves conventionally have a burner cup with absorptive wadding immersed in a supply of liquid alcohol and a main burner assembly which is ignited to produce a flame maintained by consumption of alcohol in the burner cup. For many years, outdoorsmen have used such alcohol stoves for cooking on boats or at campsites where supplies of natural gas are unavailable. In addition, alcohol stoves have been utilized by homemakers in conjunction with fondue cookers and chafing dishes placed on serving tables, dining tables, or other locations away from kitchen stoves. Examples of such alcohol stoves are disclosed by U.S. Pat. No. 466,867 to Wojidkow, U.S. Pat. No. 599,147 to Manning, et al., U.S. Pat. No. 1,036,523 to Lange, U.S. Pat. No. 1,130,501 to Erichsen, U.S. Pat. No. 3,316,957 to Stokli, et al., U.S. Pat. No. 3,606,609 to Lipper, et al., and British Patent No. 1,249,165 to Kin Hip Metal & Plastic Factory Limited.
Despite the long-standing use of alcohol stoves in the form commonly employed as fondue cookers, their operation has not been totally satisfactory due to fluctuations in flame intensity, inefficient burning due to poor alcohol-air mixing, low fuel capacity, and a relatively low maximum flame output. At start-up, the alcohol which is poured into a stove cup tends to be cold, and, as a result, relatively little alcohol evaporates. Because alcohol evaporation is needed to fuel the stove's main burner, it is often necessary to provide the stove with a start-up burner which, when ignited, warms the alcohol in the burner cup until there is sufficient alcohol evaporation to fuel the main burner. Once sufficient alcohol evaporation occurs, the main burner may be ignited. As the main burner continues burning alcohol, the stove gets progressively warmer, causing excessive alcohol evaporation and consequent high flame intensity. To control the size of the flames, a top can be placed completely or partially over the cup. Alternatively, burning can be controlled by providng the cup with a perforated nozzle extending upwardly from the cup to mix efficiently air and fuel.
One solution to these problems has been to provide a separate, alcohol tank from which alcohol can be dispensed in a controlled manner. In such systems, alcohol must be conveyed to the burner by gas pressurization of the tank or be elevating the tank to effect gravity flow of alcohol to the burner. Alcohol is heated to vaporization when it approaches or enters the burner. During operation, the vaporized alcohol mixes with air at the burner to achieve combustion. Start-up necessitates preheating the burner to effect vaporization. Although such stoves achieve higher output, greater efficiency, and better control than fondue cookers; stoves with separate burners and tanks are costly, complex, bulky, and difficult to start-up.
U.S. Pat. No. 4,416,617 to Ebbeson discloses another type of alcohol stove which has been used on boats for cooking. This device is constructed somewhat like a fondue cooker but is rather large to achieve adequate heating and is provided with a nozzle to reduce flame diameter and to achieve some mixing with air. The Ebbeson stove still has the disadvantages of somewhat inefficient combustion and difficult start-up.